Chain mail was good - if it wasn't then it wouldn't have been used for all those hundreds of yearsWith the minor quibble that much of that armor developed *after* the introduction of gunpowder! Just nitpicking--I understand what you mean.
SOMEone should make a case for MAIL, though! A nearly impenetrable metal skin with unlimited mobility and ventillation, that can be put on in a matter of moments. Even modern materials can't match that. It's the only type of armor that has been in continuous use since 300 BC--still used for butchers' gloves and anti-shark suits.
It protected against cut but not so much against thrusts and missiles like arrows
Superior plate armor developed in the late middle ages and was proof against arrows - the French knights at Agincourt 1415 were much better protected than those at Crecy in 1345....gunpowder was used at Crecy but it can hardly be regarded as part of the gunpowder age